Percussive tool



April 13 192s. 1,580,202

' G- M. JAFFRENNOU PERCUSSIVE TOOL Filed Sept. 50, 1922 2 Sheets-Sheet 1 1 Guillaume Man; Iaffnnnou INVENTOR:

1414 Attorney.

April 13 19 26.

G. M. JAFFRENNOU PERCUSSIVE TOOL Fil ed Sept. 30, 1922 2 Shae t 2 @II 'IW? Patented Apr. 13, 1926.

UNITED STATES 1,580,202 PATENT. OFFICE. I

GUILLAUME mam Jurrmnn'orr, or rears, rnancn.

PERGUSSIVE TOOL.

Application filed September 30, 1922. Serial No. 591,461.

To all whom. it may concern:

' cussive tool or striking device which may be used in all cases where it is required to execute work by repeated impact such as in' the operations of rivetting, chiseling, surface dresslng, boiler scale removal, mine and quarry drilling, pavement or road pounding,

etc.

The improved tool comprises a casing in which the tool (or tool holder) is guided and wherein a striking member is imparted acircular movement, said member acting in its movement to strike the shank of the tool or tool holder and rebounding freely after each impact in order to clear the tool shank. Other characteristic features of the invention will appear from the following description.

In the' accompanying drawing which shows by way of example two forms of construction of the improved percussive tool,

Fig. 1 is a lengthwise section of the appapart The ball 6 is carried round by ratus on the line A-A (Fig. 2).

Fig. 2 is a diametral section on the line 13-13 (Fig. 1).

Fig. 3 is a lengthwise-section of a modification along D-'D (Fig. 4).

Fig. 4 is a diametral section along CC (Fig. 3). I

As shown in Figs. 1 and 2, the apparatus comprises a casing 1 traversed by a shaft 2 which '1s driven by a motor either directly or by a flexible transmission with or without the insertion of a clutch 3.

To the driving shaft 2 is keyed a drums. This drum drives the striking member which is formed by a ball, 6. The combination of the drum 4 and ball 6 is balanced by a heayy t 1e drum 4 by friction and is acted upon by centrifugal force, so that it will always come to the position shown i.. e. at the greatest distance posslble from the drum axis. It will thus act by repeated impact-upon the shank 7 which is held for example in the support 8. The whole machine is moved about by a handle 9. Y

To afford the release of the striking mass after each impact, the drum 4 has an inner channel 13 for the passage of the shank 7 of In the arms 14 of the tool or tool holder. the crank shaft are mountedtwo rollers 15 which are jonrnalled in their seats and engage at one end into recesses 16 formed in the opposite faces of the striking member 6'. The latter has the form of a cylinder whose generatrix is slightly convex and is a solid part, this being an essential condition in order to withstand the heavy shocks required in certain kinds of work. The rollers 15 are held laterally in their seats by the shoulders 17 on the casing 11 and cover plate 12.

In operation, the crank shaft 4 being r0- tated, the striking member 6 is entrained by the rollers 14, and this member submitted to centrifugal force takes with respect to the crank shaft 4 and the rollers 15 the position shown in the drawing. In its movement, the striking member comes into contact with the shank of the impact piece 7 and transmits to it a shock on its axis. This shock entirely .utilizes the tangential component of the vis viva of the striker. After the shock, the member 6' is again acted upon by the rollers 15 and it is again affected by the centrifugal force, and the shock is thus renewed at each revolution.

The outer diameter of the striker 6, the diameter of the two recesses 16, the diameter of the rollers 15, andthe distances (1 and d are so determined that the striker 6' can be is rotatably released after each shock and can resume its circular movement.

Various constructlonal modifications in detall may obviousl Y be made in the devices described without for this reason departing tion a casing having a passage through the form of a cylindrical mass and provided which the shank of the tool is adapted tovexwith a circular recess ineach of its lateral 10 tend; a cover plate adapted to close said sides, and two rollers journalled on said casing laterally, a crank shaft across said arms and engaging into said recesses re- 5 casing, two cheeks balancing said shaft and. spective-ly.

leaving between themselves a channel for In testimony whereof I have signed my the path of said shank, two arms integral name to this specification. with said shaft, a striking member having GUlU-AUME MARIE JAFFRENNOU- 

